<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			
			body{
				padding: 0;
				margin: 0;
				display: flex;
				width: 800px;
				margin: 0 auto;
			}
			.a{
				width: 100px;
				height: 100vh;
				background-color: red;
			}
			.b{
				width: 700px;
				height: 100vh;
				background-color: blue;
			}
		</style>
	</head>
	<body>
		<div class="a">A</div>
		<div class="b">B</div>
		<script src="js/jquery.3.6.3.js"></script>
		<script>
			$(window).resize(function(e){
				console.log("窗口发送了改变",$(window).innerWidth());
				if($(window).innerWidth()<=700){
					$(".a").hide();
				}else if($(window).innerWidth()>=800){
					$(".a").show();
				}
			})
		</script>
	</body>
</html>